1. Technical Field:
In areas such as work spaces contaminated with friable articles such as asbestos fibers during asbestos removal therein, it is essential that no air-borne particles such as the friable asbestos fibers leave the work area.
2. Description of the Prior Art:
Prior to the present invention, this has been facilitated by providing overlapping polyethylene sheets between the work area and adjacent areas including decontamination areas by providing overlapping polyethylene sheets between the decontamination area and the work area. Air moving into the work area responsive to the operation of negative air machines communicating therewith moves through the overlapping plastic sheets which usually also provide means for personal entering and leaving the work area. The overlapping plastic sheets are so arranged that at any time the negative air pressure in the work area is lost, the sheets preclude ambient air in the work area from passing out of the work area and insure against a positive pressure occurring in the work area causing contaminated air from the work area passing outwardly therefrom.
The present invention relates to an inflow and outflow HEPA vent filter device positioned in the air inlet to the work area which is usually in communication with a decontamination area. Air entering and air exiting the work area through the air inlet must pass through the device and therefore the air-borne friable asbestos particles or the like are removed and the decontamination or other areas around the work area not contaminated with the friable asbestos fibers.